Pj. Bardroff et al., ENDOSCOPY IN THE PAUL TRAP - MEASUREMENT OF THE VIBRATORY QUANTUM STATE OF A SINGLE-ION, Physical review letters, 77(11), 1996, pp. 2198-2201
We reconstruct the density operator of the center-of-mass motion of an
ion stored in a Paul trap by mapping the dynamics of the motion onto
the internal dynamics of the ion. Our technique takes into account the
explicit time dependence of the trap potential, operates outside the
Lamb-Dicke limit, and is not restricted to pure states. We demonstrate
the feasibility of this method using the example of a damped Schrodin
ger cat state.